How to encode 4-channel (4.0) PCM with Nero AAC?, The encoder chokes on them… Options

[moozooh]

Hello, I have a problem.

I've been trying to feed Nero's AAC encoder v1.0.7.0 a 4-channel (4.0, each channel is technically monaural) PCM/WAV file, but it won't eat it.

The error message follows:

CODE

ERROR: Could not initialize SBR

When I'm trying to force LC profile instead, the error message changes to:

CODE

ERROR: unsupported channel configuration

I know it's not really a popular (or even feasible) channel configuration, but it shouldn't matter as long as there's an application. I also know AAC should be able to cope with a lot of channels, let alone something as trivial as 4.0.

So, the questions are:
- what am I doing wrong?
- is there a way to fix it?
- is this a bug, or Nero AAC just isn't planning to support this channel configuration?

[moozooh]

Umm, guys, seriously… I know doubleposting is bad, but the question is begging an answer. This is an actual problem and I would like to hear a solution because the means supplied with the encoder release package fail in helping to carry it out.

Furthermore, the thread hasn't fallen much down the page that AAC tech guys are well aware of. Is my question being ignored, or is every one of them on a internet-free vacation? Sorry if I sound whiny, but I don't know where else to ask.

[Ojay]

I've been trying to feed Nero's AAC encoder v1.0.7.0 a 4-channel (4.0, each channel is technically monaural) PCM/WAV file, but it won't eat it.

I know it's not really a popular (or even feasible) channel configuration, but it shouldn't matter as long as there's an application. I also know AAC should be able to cope with a lot of channels, let alone something as trivial as 4.0.

So, the questions are:
- what am I doing wrong?
- is there a way to fix it?
- is this a bug, or Nero AAC just isn't planning to support this channel configuration?

I can't tell you what you are doing wrong because you didn't provide the necessary info (encoding parameters etc.) and that is also the reason why you didn't get any answer and your questions are ignored here (hey, this is a TECH forum!!!).... Nevertheless, I will try to outline a few more general solutions...

1st solution: add a fifth WAV file with silence having the same length as the other four channels. You can do it with Audacity. This results in a 5.0 configuration. That should do it as a workaround if the Nero encoder doesn't accept the 4.0 configuration....

2nd solution as a fallback: tell the encoder (commandline) to use a 4.0 WAV file with all parameters properly set (bitrate, bitwidth, etc.) If you are using LARGE wav files (>2GB) then it might be necessary to use the Microsoft "WAV extensible" format but I am not sure, it depends on your files. As a workaround you can feed the files as raw PCM data into the encoder for files >2GB but in that case you will need to tell the encoder all relevant file parameters (bitrate, bitwidth, channel configuration, frequency) by hand. If all that doesn't work, try the 2nd solution below.

This post has been edited by Ojay: Apr 28 2007, 14:47

[moozooh]

The commandline didn't matter, because, as I said, the encoder refused to work with any commandline. Try it. Start with "-br 96000 -2pass", which is the one I tried in the first place (not that Nero's encoder allows much commandline variation, anyway).

I have uploaded a random 4ch file (4.0, 44100 Hz), converted with foobar2000 from stereo via DSP (I have also tried another 4ch files, including those not created with foobar). I don't have Audacity and won't have the means to use it in the next few days, so I have no reliable ways to edit multichannel PCM files currently. Also, I don't consider converting it to 5.0 with a dummy center channel a good solution, although it might be the one I'll have to resort to if there won't be any other choice.

Regarding encoding from stdin, that might be a good solution, but unfortunately, I don't know how. The encoder's readme simply mirrors its -help option, which is rather useless in this case.

This post has been edited by Mo0zOoH: Apr 28 2007, 15:38

[john33]

Having had a quick look at this in a hex editor, it does not have a WAVFORMATEXTENSIBLE header, may be that's an issue?

[moozooh]

Having had a quick look at this in a hex editor, it does not have a WAVFORMATEXTENSIBLE header, may be that's an issue?

Could you upload a short sample of 4.0 WAVFORMATEXTENSIBLE file so I could try it and see if it works? (Or maybe you could try it yourself to see if there are further errors on my end…)

[eevan]

Having had a quick look at this in a hex editor, it does not have a WAVFORMATEXTENSIBLE header, may be that's an issue?

I think that's not an issue because I've easily encoded 5.1 wav with the "old style" wav header. It seems that something else is the problem, but I can't figure out what.

Edit:

WMA 9 Professional also encodes only to 5.1. You must provide files with digital silence for all unused channels. Although, Nero in it's white paper says "Maximum Number of Channels: 8 (7.1 Speaker Configuration)".

This post has been edited by eevan: Apr 28 2007, 19:31

[john33]

Having had a quick look at this in a hex editor, it does not have a WAVFORMATEXTENSIBLE header, may be that's an issue?

Could you upload a short sample of 4.0 WAVFORMATEXTENSIBLE file so I could try it and see if it works? (Or maybe you could try it yourself to see if there are further errors on my end…)

I believe this has the correct header: http://homepage.ntlworld.com/jfe1205/4ch.zip

[moozooh]

I believe this has the correct header: http://homepage.ntlworld.com/jfe1205/4ch.zip

Just tried it, the encoder gives the same two errors mentioned before depending on the bitrate/profile.

[john33]

I believe this has the correct header: http://homepage.ntlworld.com/jfe1205/4ch.zip

Just tried it, the encoder gives the same two errors mentioned before depending on the bitrate/profile.

Hmm, in that case I'll have to pass to someone more knowledgeable about the NeroAAC encoder.

[starcy]

You can't encode this because is not a standard for multichannel, it must have 6 channels at least, or two for stereo. Any AAC encoder will reject this.

[moozooh]

You can't encode this because is not a standard for multichannel, it must have 6 channels at least, or two for stereo. Any AAC encoder will reject this.

Two things:
1) get your facts straight;
2) why is it that any AAC encoder would not encode 4.0 only because it isn't as widely used as 5.1?

This post has been edited by Mo0zOoH: Apr 29 2007, 14:54

[Ojay]

add a fifth WAV file with silence having the same length as the other four channels. You can do it with Audacity. This results in a 5.0 configuration. That should do it as a workaround if the Nero encoder doesn't accept the 4.0 configuration....

read through the thread and I think, the solution is to add two PCM channels (WAV files) with digital silence, not just one. 5.1 channels with two silent channels (center and 0.1 channel) can be considered 4.0. The encoder compresses the two silent channels heavily so that they do not contribute to the total size of the final 5.1 file.